From: Julian Seward <jseward@acm.org>
Date: Wed, 11 Dec 2013 16:49:46 +0000 (+0000)
Subject: Select expensive add/sub/cmp interpretations for blocks containing
X-Git-Tag: svn/VALGRIND_3_10_0~679
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=19f49b677b29dc6653c6d17e90dc9a7cfcc75fed;p=thirdparty%2Fvalgrind.git

Select expensive add/sub/cmp interpretations for blocks containing
Iop_GetMSBs8x16, since the presence of those usually implies PMOVMSKB
instructions in the block, which can mean "inlined string operations".
Reduces the noise level a lot in some icc12 -O2 generated sequences.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13757
---

diff --git a/memcheck/mc_translate.c b/memcheck/mc_translate.c
index d4b703c2b0..b654816815 100644
--- a/memcheck/mc_translate.c
+++ b/memcheck/mc_translate.c
@@ -5736,6 +5736,8 @@ static Bool isBogusAtom ( IRAtom* at )
    return (/*32*/    n == 0xFEFEFEFFULL
            /*32*/ || n == 0x80808080ULL
            /*32*/ || n == 0x7F7F7F7FULL
+           /*32*/ || n == 0x7EFEFEFFULL
+           /*32*/ || n == 0x81010100ULL
            /*64*/ || n == 0xFFFFFFFFFEFEFEFFULL
            /*64*/ || n == 0xFEFEFEFEFEFEFEFFULL
            /*64*/ || n == 0x0000000000008080ULL
@@ -5760,7 +5762,8 @@ static Bool checkForBogusLiterals ( /*FLAT*/ IRStmt* st )
             case Iex_Const:
                return isBogusAtom(e);
             case Iex_Unop: 
-               return isBogusAtom(e->Iex.Unop.arg);
+               return isBogusAtom(e->Iex.Unop.arg)
+                      || e->Iex.Unop.op == Iop_GetMSBs8x16;
             case Iex_GetI:
                return isBogusAtom(e->Iex.GetI.ix);
             case Iex_Binop: